The most common method of erecting concrete walls and foundations today utilizes forms constructed of plywood and timber framing. Reinforcement can be provided by installing rebar or other metal reinforcement in the space between the forms. In many installations, metal reinforcement is installed prior to building the forms. After the space is filled with concrete and the concrete is allowed to set, the wooden forms are removed.
This type of procedure has proved to be expensive for a variety of reasons. The wood itself is expensive. Due to the density of the wood, transportation to the construction site is quite costly. In addition, qualified carpenters are needed to erect the wooden forms. Furthermore, workers must later come back after the concrete is poured to remove the forms. There are also seasonal costs when the concrete is poured during cold weather because the wood forms must be insulated by applying blankets to the exposed sides and straw to the exposed surface of the concrete.
Heretofore, concrete forms of expanded polystyrene or extruded polystyrene foam have been utilized. Such foam is lightweight and, therefore, inexpensively transportable to the construction site. Such foam forms provide thermal insulation during pouring and can be left in place after the concrete is poured in order to eliminate the cost of removal and to provide insulation to the area defined by the concrete walls. Systems incorporating these features are described in our copending applications Ser. No. 167,782 filed Mar. 14, 1988 and Ser. No. 247,038 filed Sep. 20, 1988 and are incorporated herein by reference.